Audio processing methods, apparatuses, and implementations for processing digital audio input signals into analog audio output signals can be implemented or provided on a single integrated circuit (“IC”) and include a way(s) for enhancing the dynamic range (e.g., a dynamic range enhancement (“DRE”) feature/capability) of audio signals processed by the single IC. Such a DRE solution/controller is typically provided and confined within the single audio processing IC.
FIG. 1 shows an example single DRE audio processing IC 100 in accordance with the prior art. Single IC 100 comprises a path that has coupled in series a signal processing block 104, a DRE gain block 105 having a DRE gain 106, a modulator 108, a digital-to-analog converter (“DAC”) 110, and a driver 112 having a driver gain 116 as shown in FIG. 1. An audio input signal (“AUDIO IN”) 102 is received by single IC 100 and is fed into signal processing block 104. Single IC 100 provides an audio output signal (“AUDIO OUT”) 118 as the output. A DRE control block 114 is coupled to the output of signal processing block 104, and the output of DRE control block 114 is fed into the DRE gain block 105. Depending upon the criteria or manner of the DRE control, DRE control block 114 gains up or gains down the DRE gain 106 of DRE gain block 105. The product of the DRE gain 106 and the driver gain 116 may always equal one or another constant value, so the driver gain 116 is correspondingly gained down or gained up based on the respective gain up or gain down of DRE gain 106 (e.g., driver gain 116 is the inverse of DRE gain 106).
FIG. 2 shows an example audio device configuration 200 in accordance with the prior art. Audio device configuration 200 shows a mobile device or computer 202 having an earphone or headphone 201 coupled to it. The single IC 100 is located within mobile device or computer 202. In this example configuration 200, the audio processing that includes the conversion of the digital signals into analog signals and the DRE control of the audio signals are all done within the single IC 100. Thus, the earphone/headphone 201 receives the already processed and DRE controlled analog output signals 203 and 205 from mobile device or computer 202, and the analog output signals 203 and 205 are transmitted to respective earbuds or headphone speakers 204 and 206 as shown in FIG. 2.
FIG. 3 shows another example audio device configuration 300 in accordance with the prior art. Configuration 300 is similar to configuration 200 of FIG. 2, but in configuration 300, the single IC 100 is located in an external box 302 as shown in FIG. 3 instead of within mobile device or computer 202 as shown in FIG. 2. Configuration 300 shows the mobile device or computer 202 coupled to the external box 300. The mobile device or computer 202 provides an analog or digital audio signal 301 to external box 302. External box 302 is coupled to earphone or headphone 201, and external box 302, in turn, provides the analog output signals 203 and 205 to respective earbuds or headphone speakers 204 and 206 as shown in FIG. 3. Similar to configuration 200, since analog output signals 203 and 205 are being provided to the earbuds or headphone speakers 204 and 206 in configuration 300 of FIG. 3, power again is required for enabling such analog signal transmission through earphone or headphone 201. This power is typically provided by the battery or power storage unit of the mobile device or computer 202 or by a battery or power storage unit of the external box 302 if the external box 302 has such a battery or power storage unit. This power consumption of the battery or power storage unit of the mobile device or computer 202 and/or external box 302 is not desired.
Adaptive noise cancellation (“ANC”) algorithms are well known in the art and have been implemented for processing audio signals (e.g., AUDIO IN 102) in effectively cancelling or filtering ambient or background noise. In ANC processing, there is a desire to place ANC microphones as close to a user's ear as possible. ANC microphones are typically located in the mobile device or computer 202 of FIGS. 2 and 3 or in the external box 302 of FIG. 3 since they at least require a level of signal processing hardware/circuitry that is typically located in the mobile device, computer, or external box. An ANC microphone would be ideally located in an earbud/headphone speaker 204 or 206. However, locating an ANC microphone in an earbud/headphone speaker 204 or 206 has its challenges. Such challenges include but are not limited to space limitations and/or processing requirements. Thus, digital processing/communications for such ANC microphone signals has advantages and would be desired.
Thus, a number of desired reasons exist for processing audio signals as digital signals instead of analog signals. Some of these desired reasons include but are not limited to providing higher fidelity, lessening susceptibility to noise, interference and coupling effects, lessening degradation of signals along the transmission path, allowing for more sophisticated error correction algorithms, and maybe even lowering power consumption.